Office (OOXML) / .XLSX malware analysis — malicious · 34b1ae97e90558de

MALICIOUS

Office (OOXML) / .XLSX

121.7 KB Created: 2021-08-16 09:36:27 UTC Authoring application: Microsoft Excel 12.0000

MD5: c5e068c0ab35bf603fdbab891c10638c SHA-1: 9fbbf97c6a3da7dfb930327863ed576c1966c404 SHA-256: 34b1ae97e90558de2261b9b9f5108b5747dcefaec75b9d5ff40d463d6de07c71

60 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic

The critical heuristic firing indicates the presence of Excel 4.0 macros within the XLSX file. While the macro content is heavily truncated and obfuscated, the presence of such macros strongly suggests an intent to execute arbitrary code. This is commonly used to download and execute further malicious payloads. Without more discernible script content, the specific family remains unknown.

Heuristics 1

Excel 4.0 macro sheet (1 sheet(s)) critical OOXML_XLM_MACROSHEET

Spreadsheet contains an Excel 4.0 (XLM) macro sheet — XLM was a major Office malware vector during 2020-2022 and evaded many VBA-focused controls before Microsoft tightened XLM defaults. Even legitimate XLM use is rare in modern workbooks. The macro sheet is stored as XLSB/BIFF12 binary content, which many XML-only OOXML scanners miss.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.bin` `e4ee2452137629377def50e49e87646b8ad106f5b28e65493c3f361594001558`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.bin	228000 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.